WASHINGTON - US president Donald Trump had ordered the Pentagon to arrange the assassination of Syrian President Bashar al-Assad, renowned Watergate journalist Bob Woodward has said.
"Let's [expletive] kill him! Let's go in. Let's kill the [expletive] lot of them," Mr Trump is reported to have told his defence secretary Jim Mattis in a book to be released on 11 September.
Woodward's book says Mr Mattis acknowledged Mr Trump's request but then, after the conversation, told an aide he would not do "any of that".
Mr Mattis is also quoted as saying Mr Trump had the understanding of "a fifth- or sixth-grader" - the age of 10 or 11 - in understanding foreign affairs.
Woodward says chief economic adviser Gary Cohn and White House staff secretary Rob Porter removed documents from the president's desk to keep Mr Trump from signing them.
The documents would have allowed the president to withdraw from the North American Free Trade Agreement and a trade deal with South Korea.
"It felt like we were walking along the edge of the cliff perpetually," Mr Porter is quoted as saying.
Trump has condemned the book as a "con on the public". His chief of staff and defence secretary, in responses posted by the president on Twitter, described the book as "pathetic" and "fiction".
In the book, senior aides are quoted as saying they hid sensitive documents to prevent Mr Trump signing them.
They are quoted as calling him an "idiot" and a "liar".
The book - Fear: Trump in the White House,  reveals a chaotic administration having a "nervous breakdown of executive power".
Woodward is a widely respected and veteran journalist who helped expose President Richard Nixon's role in the Watergate scandal in the 1970s.
He sent out a series of tweets carrying his own views, along with statements from Defence Secretary Jim Mattis, chief of staff John Kelly and White House spokeswoman Sarah Huckabee Sanders.
Mr Trump says quotes attributed to Mr Mattis and Mr Kelly were "made up frauds, a con on the public. Likewise other stories and quotes".
He says the book is "already discredited" with "so many lies and phony sources", rejecting an allegation that he had used the terms "mentally retarded" and "dumb Southerner" to describe Attorney General Jeff Sessions.
The statement from Mr Mattis describes the book as "a product of someone's rich imagination" and adds: "The contemptuous words about the president attributed to me in Woodward's book were never uttered by me or in my presence."
The statement from Mr Kelly says: "The idea I ever called the president an idiot is not true... He always knows where I stand and he and I both know this story is total BS... This is a pathetic attempt to smear people close to President Trump."
Ms Sanders said the book was "nothing more than fabricated stories, many by former disgruntled employees, told to make the president look bad".
In an interview with the Daily Caller, Mr Trump said that "it's just another bad book", adding that Woodward "has a lot of credibility problems".
One of the main claims is that current and former aides kept sensitive documents off his desk to prevent him from signing them, or took different actions to those demanded by the president.
This amounts to an "administrative coup d'état", Woodward says.(FA)